There is no 3D autogen showing up on my scenery

There are really only three critical factors that could be inhibiting the Autogen 3D elements contained in ES scenery.

The first and most common reason is the default autogen files not being updated correctly with the ES adaptations. The files contained in the zip in this hotfix article have the required adaptations to fix this issue.

The second critical factor is that the Earth/ Simulations/ES-3D folder is active. You might try removing it from your scenery library in FSX settings , clicking OK to rebuild the scenery cfg and then adding it again manually to be absolutely sure there is no issue with that.

The third factor is just that in FSX graphics/scenery settings your FSX scenery complexity slider and Autogen complexity slider are both set above normal

With all three covered there is no known reason for the scenery not to display.